1. Field of the Invention
The present invention relates to a speed control device for controlling the speed of a vehicle rolling on a rail track. Especially, it refers to a speed controlling device for controlling the speed of a freely running transport vehicle in a shelf storage system. The device comprises a rotating breaking and accelerating means driveable at a predetermined speed and engageable with a vehicle passing the speed control device to decrease or increase the speed of the vehicle.
2. Description of the Prior Art
Speed control devices are used in automatically operated shelf storage systems, where the transport vehicles loaded with goods are not only used for storing the goods but also for transporting the goods from a receiving station to a storing station and therefrom to a exit station. The movement of such vehicles is effected by an inclination of the rail track. It is quite evident, that, therefore, the speed of these vehicles is not well predetermined, but rather varies considerably, depending on the load on the vehicle. On the other hand, it is imperative to hold the speed of the transport vehicles within certain limits. The speed may not become excessive, in order to prevent the load from being off-centered or even from falling down from the vehicle or to prevent the vehicle from jumping out of the rail track. On the other hand, there must be provided a certain minimal speed in order to prevent a vehicle from stopping, which would lead to critical situations or accidents.